RE: Subgroup to handle semantics of HTTP etc?

Hello Xiashou,

> -----Original Message-----
> From: Xiaoshu Wang [mailto:wangxiao@musc.edu] 
> Sent: 22 October 2007 18:20
> To: Williams, Stuart (HP Labs, Bristol)
> Cc: Booth, David (HP Software - Boston); W3C-TAG Group WG; 
> Alan Ruttenberg; Jonathan A Rees; Dan Connolly; Tim Berners-Lee
> Subject: Re: Subgroup to handle semantics of HTTP etc?
> 
> Williams, Stuart (HP Labs, Bristol) wrote:
> >> They may
> >> referred to as
> >>
> >> _:aPrintCopy awww:hardCopyOf <http://example.com/abook>.
> >> _:anAudio awww:soundOf <http://example.com/abook>.
> >> _:anHTMLRep awww:informationResourceOf <http://example.com/abook>.
> >> _:anPDFFile awww:informationResourceOf <http://example.com/abook>.
> >> .....
> >>
> >> Please note that my last two assertions because I think it is more 
> >> appropriate to define *information resource* as the set of all 
> >> representations of all generic URIs.  Such a view has few 
> advantages.
> >>     
> >
> > Sorry, but I am not getting this - there may be some words missing.
> >
> > Alt1: if "information resource" is the set of all representations 
> > obtainable from all generic URIs (over all time? or at an instant?) 
> > how are we to discriminate one information resource from another?
> >   
> Using b-nodes? So we can refer the html representation of 
> http://example.com/abook as _:abook a HtmlRepresentation;
>              repOf <http://example.com/abook>.
> Just like in human language, we talk about it as the "html 
> representation" of <http://example.com/abook>. Right?
> 
> A representation is bound with its master URI, so we cannot 
> talk about it without its master URI.

Hmmm... I think you are still in a tangle trying to think of
representations as resources.

Once you have lumpped all possible representations into a single set, I
don't see what distinguishing feature they have that enables you to bind
them to a b-node - it's just representation soup.

FWIW: the definition of the a resource that I suspect most of the TAG
work with is the one that I'll attribute to Roy Fielding:

	"More precisely, a resource R is a temporally varying
	membership function MR(t), which for time t maps to a set of
	entities, or values, which are equivalent. The values in the set
	may be resource representations and/or resource identifiers."

My understaning of the latter clause ("...and/or resource identifiers.")
is that it covers both redirection and content-negotiation.

Anyway... the point is that by that definition, the notion of a resource
entails all its available representations past, present and future. I
think this is close to your conceptualisation, except that in your
formulation: 

	"I think it is more 
	appropriate to define *information resource* as the set of all 
	representations of all generic URIs."

you seem to form a set from ALL representation of ALL (generic)
resources, whereas Fieldings defn (flattening out time) forms a set of
resources each of which has a sets of ALL it's possible "representations
and/or (redirection/connneg) resource identifiers". It is then the
resource which get assigned resource identifiers, *not* their
representations.

[1] http://www.ics.uci.edu/~fielding/pubs/webarch_icse2000.pdf

> >> 1) It is much easier to understand and consistent because 
> it doesn't 
> >> matter if a URI identifies a network resource, a person, or a 
> >> namespace, or an ontology.
> >>     
> >
> > I don't understand what comparison is being made here. Something is 
> > 'easier' than something else... but I'm struggling to ground the 
> > 'somethings'.
> >   
> I snip the rest.  I don't think we differ too much but only 
> on probably this one question.
> 
> Is there any distinguishable difference between a "document 
> (awww:InformationResource)" and a person?

Distinguishable by whom/what?

I don't think that I can capture all my (current) 'essential'
characteristics in a message, though I think Pat had a pretty good go
wrt to himself and what might be regarded as some eternal
characteristics [2].

I was going to say that I could/can change the state of at least some
documents by sending a message on the web (PUT/POST), whereas I can't
change your state in the same way (if you have state that is). OTOH
sending a message clearly has some impact. In large part though, this
would be equally true of a paper document - though what is printed on
the paper would be regarded as an IR, the paper copy itself would not.

Short answer is...  yes I think that there are... but pinning down what
precisely they are is hard.

[2] http://www.ihmc.us/users/phayes/PatHayes

> Current, AWWW thinks so (from my understanding).  I think 
> not, which I just responded to Noah's question.
> 
> Hence, I propose to use "information resource" for 
> *representations* because it feels - at least to me - natural 
> to think that  in the web we work with "information resource" 
> to understand things in the world.

"... I propose to use "information resource" for *representations*..."

Please don't do that... I think that would contribute more confusion
than light.

>  A "document" located 
> somewhere in the network, therefore, is not an information 
> resource.  It is just an ordinary *thing* in the world, like 
> a book, a person, etc...

Thing is a word I could use instead of resource - that's already been
discussed by others on another thread.

> Xiaoshu

Stuart
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Received on Tuesday, 23 October 2007 08:15:03 UTC